[Bug]: Tag Navigation & Missing CSS

[rolfschumacher]

The following summary is a revised text generated by Claude, assisting to find the cause of unwanted NC Files behavior.

Nextcloud 33 Bug Report: Tag Navigation & Missing CSS

Instance: selfhosted, abbreviated here by my-nc-url
Nextcloud Version: 33.0.2
Server: Ubuntu 24.04, Apache2 reverse proxy, Let's Encrypt SSL
Date: 2026-05-06

---

Bug 1: Clicking a Tag in Files View Causes 404

Symptom

Clicking a system tag in the Files navigation sidebar does nothing. The browser console (F12) shows:

PROPFIND https://my-nc-url/remote.php/dav/files/rsc/15/ 404 (Not Found)

followed by:

[ERROR] files: Error while fetching content — Error: Invalid response: 404 Not Found

Root Cause

The systemtags app constructs the wrong WebDAV path when the user clicks a tag entry in the Files sidebar. Instead of using the correct DAV endpoint for tag-based file listing:

/remote.php/dav/systemtags-relations/files/{tagId}/

it incorrectly routes the request through the regular files endpoint:

/remote.php/dav/files/{username}/{tagId}/

Here, 15 is the system tag ID (confirmed via SELECT * FROM oc_systemtag WHERE id = 15), not a file ID or folder name.

The call stack in the console confirms the wrong action is triggered:

exec @ openFolderAction.ts:36
execDefaultAction @ FileEntryMixin.ts:331
click @ FileEntry.vue:5
...
Files.ts:34

Prior Art

This is a regression of a previously fixed bug:

• PR fix(systemtags): Correctly load tagged files in "tags"-files-view #47120 – fix(systemtags): Correctly load tagged files in "tags"-files-view
  fix(systemtags): Correctly load tagged files in "tags"-files-view #47120

When splitting the path /{ID}, the resulting array is ['', '{ID}'] — the code was using index [0] (empty string) instead of the last element, causing the wrong path to be constructed.

The fix was backported to stable28 and stable29 but has apparently regressed in Nextcloud 33.

---

Bug 2: Missing CSS File files_versions/css/sidebar-tab.css

Symptom

The browser console shows:

Refused to apply style from
'https://my-nc-url/apps/files_versions/css/sidebar-tab.css?v=...'
because its MIME type ('text/html') is not a supported stylesheet MIME type,
and strict MIME checking is enabled.

A direct request confirms the file is missing:

curl -I https://my-nc-url/apps/files_versions/css/sidebar-tab.css
→ HTTP/1.1 404 Not Found
   Content-Type: text/html

Root Cause

The files_versions app in Nextcloud 33 contains no css/ directory at all:

find /var/www/html/nextcloud/apps/files_versions -name "*.css"
# → (no output)

Nextcloud 33 migrated CSS into Vite/JS bundles, but some reference to the old static file
sidebar-tab.css was apparently not updated, causing the browser to request a file that no
longer exists on disk. The server returns a Nextcloud HTML error page, which the browser
then rejects as an invalid stylesheet.

Impact

Non-fatal: the missing stylesheet may cause minor visual glitches in the file versions
sidebar tab, but does not break core functionality.

---

Investigation Steps Taken

Step	Command / Action	Finding
Check filecache	SELECT fileid, path FROM oc_filecache WHERE fileid = 15	Empty — 15 is not a file ID
Check tag mapping	SELECT * FROM oc_systemtag_object_mapping WHERE objectid = 15	Empty
Identify 15	SELECT * FROM oc_systemtag WHERE id = 15	Confirmed: 15 is a system tag ID
Check CSS on disk	find /var/www/html/nextcloud/apps/files_versions -name "*.css"	No CSS files exist in files_versions
Verify via curl	curl -I .../files_versions/css/sidebar-tab.css	HTTP 404, text/html
Check NC version	occ status	Nextcloud 33.0.2
Check app version	occ app:list | grep -i tag	systemtags: 1.23.0

[joshtrichards]

Bug 2: Missing CSS File files_versions/css/sidebar-tab.css

This matter was addressed in the v33.0.3 maintenance release.